ABSTRACT Major psychiatric illnesses are increasingly understood as disorders of brain development, which has led to large-scale studies of youth that combine multi-modal neuroimaging with clinical phenotyping. Together, such data have emphasized the promise of objective ?growth charts? of brain development. However, synergies across major efforts remains unrealized due to use of different clinical instruments, different scanning protocols, challenges in informatics, and difficulties in data integration. In this proposal, we will overcome these obstacles by leveraging advances in multivariate harmonization and analysis techniques to build highly reproducible growth charts of human brain development. To do this, we will aggregate and harmonize eight existing large-scale developmental imaging studies, comprising over 10,000 participants between the age of 5- 24 (Aim 1). We will use this harmonized data to build generalizable indices of normal network brain development (Aim 2). Finally, developmental abnormalities within specific brain networks will be linked to dimensions of psychopathology (Aim 3). Critically, all code, data, and derived indices will be shared publicly, creating a massive new resource to accelerate research in the developmental neuroscience community (Aim 4). In sum, this proposal will have provide a new data resource, yield reproducible growth charts of brain development, and delineate novel mechanisms regarding the developmental basis of psychopathology in youth.